Re: [PATCH] PCI: Data corruption happening due to race condition

[Lukas Wunner <lukas@wunner.de>]

On Mon, Jun 25, 2018 at 03:40:46PM +0530, Hari Vyas wrote:
> When a pci device is detected, a variable is_added is set to
> 1 in pci device structure and proc, sys entries are created.
> 
> When a pci device is removed, first is_added is checked for one
> and then device is detached with clearing of proc and sys
> entries and at end, is_added is set to 0.
> 
> is_added and is_busmaster are bit fields in pci_dev structure
> sharing same memory location.
> 
> A strange issue was observed with multiple times removal and
> rescan of a pcie nvme device using sysfs commands where is_added
> flag was observed as zero instead of one while removing device
> and proc,sys entries are not cleared.

Where exactly was is_added incorrectly observed as 0?  Normally
addition and removal of devices are serialized using
pci_lock_rescan_remove(), maybe this is missing somewhere?

Thanks,

Lukas